If you haven’t seen an epileptic seizure firsthand, you may have an image of one in your mind: the clenched teeth, the flailing limbs.
But some seizures aren’t so obvious, as demonstrated in this “sonified seizure,” produced in collaboration between a Stanford neurologist and a music professor, who together translated a patient’s EEG signals into sound.
In it, a woman with epilepsy sits calmly in her hospital bed, talking and acting normally, despite the fact that a seizure is building up steam inside her right hemisphere.
As the right-side seizure subsides around 1:50, the left side of the brain begins to seize. This time, the woman becomes mute and confused. By 2:20, both hemispheres have calmed, leaving the patient disoriented, says her doctor, Stanford’s Josef Parvizi.
Parvizi made the EEG recording, or electroencephalogram, during the patient’s stay at Stanford Hospital, where she was undergoing brain surgery to treat her intractable epilepsy.
In what’s typically a two-stage process, surgeons first implant electrodes directly into a patient’s brain to record the source of the seizures. Then, a week later, they remove the problematic brain tissue, leaving this patient, and many more, seizure free.
Music inside the brain echoes music produced by the brain
Parvizi brought EEG recordings to Chris Chafe, a Stanford music professor responsible for the “Tomato Quintet,” which sonified the carbon dioxide releases from five vats of ripening tomatoes, among other projects.
Using human-like tones, Chafe synthesized the patient’s brain's electrical signals into sound.
Chafe was surprised, he says, by patterns that struck him as musical.
“I said ‘hey, to me this sounds a little bit like Dixieland jazz,” says Chafe.
A future diagnostic tool
Parvizi and Chafe are working on a prototype of a portable device that could translate brain activity into sound. Unlike this project, the device would record brain signals non-invasively, without requiring surgery.
The “gold standard,” for such recordings is an EEG, says Parvizi. But those can take a while to set up. The sound device could be a simpler and faster way to detect when a patient is in the midst of a non-convulsive seizure.
“This is the quickest way of getting to know what’s happening inside the brain. It’s like a stethoscope. You listen to the heart to see if there’s a heartbeat and see if it’s normal.”
Epilepsy as a window into the brain
The seizure sonification work is just one part of a broad and dramatic area of research in which epilepsy patients perform starring roles.
Recently, we told the story of Nate Bennett, from Santa Cruz, who participated in brain mapping research during his stay at Stanford Hospital.
But since we're talking about epilepsy again, I can't resist sharing a couple other clips that didn't make it into that piece.
What's amazing about this research is that it lets scientists, including Dr. Parvizi, stimulate parts of the brain directly to see what happens.
There may be no more precise way to "map" the human brain, determining -- on the order of milimeters -- which parts of it control which functions.
Along the way, it's an experiment in mind control.
Scientists who do this work control their patients' subjective experience, make them believe things are happening which are actually not.
Here's a clip where Dr. Parvizi injected a tiny, painless jolts of electricity into Nate's brain, with a very strange result.
At another point in the process, Nate felt like he was being poked. At another, when Parvizi sent an electrical signal to a part of the brain called the anterior cingulate, Nate felt an urge to shout "jinx," but was unable.
And here's another video from some earlier Parvizi research using the same method, this time on a patient named Ron Blackwell, from Santa Clara.
Creepy, right? We'll have more on this research in coming months.